Re: [pbs-devel] [RFC PATCH proxmox-backup] server/rest: disallow non-protected api calls in privileged environment

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

On 02.03.21 16:31, Dominik Csapak wrote:
> to prevent potential abuse of non-protected api calls as root
> 

this breaks important CLI tools using client::connect_to_localhost
i.e., proxmox-backup-manager and proxmox-tape and maybe others which
connect still manually.

> Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
> ---
> this is a rather theoretical security improvement, i am not sure if we
> want this? it would only guard against an unprotected api call that somehow

no, such stuff only tends to break things while not providing any value...
lets keep theoretical security improvements also theoretical..

> allows code execution. this could then be abused to connect to the
> daemon and reabuse the same api call, but with root permissions

with magically generating a ticket and circumventing permission checks
how exactly?

> 
> also if we want this, maybe this would be good to have in pve too?

no


> 
>  src/server/rest.rs | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/src/server/rest.rs b/src/server/rest.rs
> index 9bf494fd..6b170b7f 100644
> --- a/src/server/rest.rs
> +++ b/src/server/rest.rs
> @@ -750,6 +750,9 @@ async fn handle_request(
>  
>                      let result = if api_method.protected && env_type == RpcEnvironmentType::PUBLIC {
>                          proxy_protected_request(api_method, parts, body, peer).await
> +                    } else if !api_method.protected && env_type == RpcEnvironmentType::PRIVILEGED {
> +                        let err = http_err!(FORBIDDEN, "invalid server request");
> +                        return Ok((formatter.format_error)(err));
>                      } else {
>                          handle_api_request(rpcenv, api_method, formatter, parts, body, uri_param).await
>                      };
>